Related Experiment Videos
Digoxin-like immunoreactive substance: monoclonal and polyclonal RIA and FPIA compared
P Mojaverian1, P J Green, R K Jhangiania
1Department of Medicine, Jefferson Medical College, Philadelphia, Pennsylvania.
Journal of Pharmaceutical and Biomedical Analysis
|January 1, 1989
Summary
Different digoxin immunoassays vary in their sensitivity to digoxin-like immunoreactive substance (DLIS). Fluorescence Polarization Immunoassay (FPIA) and Clinical Assay (CA) showed the highest cross-reactivity, impacting accuracy in samples with elevated DLIS.
Area of Science:
- Clinical Chemistry
- Immunoassay Technology
- Endocrinology
Background:
- Digoxin-like immunoreactive substance (DLIS) is an endogenous compound that can interfere with digoxin measurements.
- Variations in DLIS levels are observed in conditions such as uremia, pregnancy, and in cord blood.
Purpose of the Study:
- To evaluate the interference of DLIS in various commercial digoxin immunoassay systems.
- To compare the cross-reactivity of polyclonal radioimmunoassay (RIA) systems, a monoclonal antibody (MA) assay, and a Fluorescence Polarization Immunoassay (FPIA).
Main Methods:
- DLIS concentrations were measured in 34 samples (uremic, third-trimester pregnancy, cord blood, normal) using six different immunoassay systems.
- Assays included four polyclonal RIA systems (CA, CI, DP, KK), one MA assay, and one FPIA.
Main Results:
- Cord blood samples generally showed higher DLIS concentrations.
- FPIA and CA exhibited maximal cross-reactivity with DLIS, while MA and DP showed minimal interference.
- DLIS levels in uremic subjects were below the detection limit for most assays.
- Re-analysis of cord blood samples using FPIA yielded higher DLIS concentrations, potentially due to changes in reagents and sample handling.
Conclusions:
- The choice of digoxin immunoassay significantly impacts results in the presence of DLIS.
- FPIA and CA are more susceptible to DLIS interference, particularly in cord blood and pregnancy samples.
- Standardization of sample preparation and assay methodology is crucial for accurate digoxin measurements when DLIS is present.